1. Field of the Invention
This invention relates generally to X-ray apparatus and more particularly to apparatus for use in cinefluorography employing a pair of motion picture cameras and image intensifier tubes adapted for biplane operation.
2. Description of the Prior Art
If two orthogonal X-ray beams are directed toward their respective receivers simultaneously, whether by accident or by design, the object being radiated by X-rays tends to scatter radiation omni-directionally, resulting in radiation directed to one receiver being diverted to and causing fogging at the other receiver situated in the orthogonal plane. By providing means to synchronize the position of the cinecamera shutters in such a way that if one shutter is open while the other is closed, and vice versa, two desired effects are obtained. First, since the opening of the shutter normally triggers the X-ray exposure, the exposures are produced alternately in two orthogonal planes. Secondly, since the X-ray exposure and open shutter are coincidental only in the same plane, the problem of cross scattered radiation is diminished, if not eliminated.
X-ray cine biplane operation is a well known technique. Where a single frame speed e.g. 60 frames per second (fps) is utilized, synchronous AC motors can be utilized to drive the cameras; however, synchronous motors, particularly polarized synchronous motors, are not readily adaptable to synchronous speed control where multispeed operation of the cameras is desired. In such applications, synchronized DC motors are normally utilized.